JESSICA SITS BESIDE NICK'S PORN STAR

It's every Hollywood husband's worst nightmare - his wife being seated next to the sexy porn star who nearly wrecked his marriage! But that's exactly what happened to singer Nick Lachey when he and gorgeous blonde Jessica Simpson were placed next to another famous Jessica - busty Jessica Jaymes, the X-rated movie star who stripped and put on a private show for Nick and his friends.

Talk about being on the hot seat!

Nick seemed terrified that the two women would start talking, or even worse, start fighting in the crowded Los Angeles nightclub Avalon, where hundreds had gathered to see Justin Timberlake, Santana and James Brown perform a tsunami relief concert February 11. Three months earlier, The ENQUIRER revealed how Jaymes, star of "If These Hips Could Talk," performed a lesbian sex show with another porn star at an October bachelor party that Nick attended for a sound engineer buddy.

When Jessica found out, she and Nick had a huge fight, say sources.

FLIRTING The word in Hollywood is that Nick and Jessica's marriage is hanging by a thread because of his flirting and partying with women while Jessica has been away shooting "The Dukes Of Hazzard" movie.

If his wife recognized the porn actress sitting next to her, Nick knew he and his "Newlyweds" co-star might soon be newly divorced, said the insider.

"Nick's jaw dropped when he saw his wife was just inches from Jessica Jaymes," an insider told The ENQUIRER. "Thank God, Jessica Simpson was clueless. She had no idea that the woman sitting near her was the same one who had entertained her husband.

"Nick looked obviously uncomfortable, but he tried his best not to let on. It would have been disastrous if the women started brawling."

The harried husband hoped to get through the evening without a confrontation, and he was sweating bullets each time the two Jessicas came near each other, said the insider. "Both women were sitting so close at one point they were actually rubbing shoulders," the insider added.

"They nodded and smiled at one another, but fortunately for Nick, Jessica Jaymes didn't let on."

At one point Nick leaned in and said something to Jaymes when his wife wasn't paying attention. "He was probably pleading with her to please move to another table," said the insider.

CRISIS MODE But just then, a flash went off and Nick freaked out - someone had snapped a picture of him whispering in Jaymes' ear. "Nick sent his enormous bodyguard over to confiscate the camera phone," said the insider. "He went into crisis mode - reaching across the table and snatching the phone away from a concertgoer."

Seconds later, the bodyguard huddled with the club's security chief and made hasty arrangements to have Jaymes and her date move to another table.

"Luckily for Nick, Jessica Jaymes didn't complain or say anything. She just picked up her purse and walked away with her date to another table, far away from Nick," said the insider.

"The entire incident happened so fast that no one really noticed, especially not Jessica Simpson."